To "scan", as the term will be used herein, means to convert visually perceptible information, by electo-optical means, into a digital format. It is known in the art to scan printed material into such a digital format for manipulation and use within a digital computer. Early success in this field primarily involved the scanning of pictures, and the like, since the information contained within a pictorial image can be stored, manipulated, transmitted and received in digital format without any need to identify the content of the image. Typically, scanning produces a "bit mapped" image. That is, a record is made regarding a plurality of pixel locations forming a data grid corresponding to the original image. In the simplest form, the data for each pixel is strictly binary, representing either a darkened pixel location or a relatively light pixel location. In more sophisticated "gray scale" scanning, a record is made of the relative darkness of each pixel location within a gradient of values. In color scanning, a record is made of the color content of a plurality of pixel locations in the image. In any case, pictorial data may be stored in such bit mapped format.
Of course, since computers excel in the manipulation of textual and numerical data, it has clearly been desirable to import such data directly from printed matter into the computer, thus avoiding the necessity of manual entry of such data. However, the introduction of textual and numerical data into a computer presents an additional problem. It is not sufficient merely to import an image of the data. Rather, the computer must "recognize" the data contained within the image and convert it into a format usable by the computer (such as "ASCII" data format, or the like). In order to accomplish this purpose a category of software known as Optical Character Recognition ("OCR") software has been developed. Early attempts at OCR software were relatively crude in that only particular type faces and sizes could be recognized, and errors were so common that the OCR software was only marginally useful. However, more recent efforts at OCR provide a considerable improvement. Modern OCR software is increasingly accurate and can recognize a wide variety of type faces. Indeed, OCR software is being advanced to the point that handwriting may be recognized and deciphered.
Given the proliferation of OCR software and the ready availability of inexpensive yet powerful computers in which such software can be used, we are now presented with the opportunity of importing data at will from printed material into our computers. Much benefit can be derived from this development. Entire pages of text can be imported into word processing systems for future reference and other purposes. An important advantage of the OCR process is that a page of data in ASCII format (or other digital format) takes up a very much lesser portion of the storage capacity of a computer than does a bit mapped image of the page. Therefore, much more data can be archived, to later be called up on a computer screen or printed out for the user's benefit. However, even this is not the greatest advantage of the OCR process. Users are finding that the greatest benefit is that short passages, quotations, and the like can be integrated into the user's own documents. In many fields of endeavor this is an extremely important benefit. As just one example, in doing legal research it is necessary to cull through many volumes of reference materials taking short passages and citations from each. In subsequently writing a legal brief based upon such research, the user must accurately reproduce these passages. Formerly, the user was required to make notes (or photocopies) as the material was researched, and then later to type the passages on the computer keyboard so that they could be included in a word processor created brief or other such document. Using the OCR technology, such passages can be directly imported into the user's text.
Today, available scanners are generally sheet type scanners which scan an entire page of information in a single operation, or hand held type scanners which can scan a section of a page, such as a strip about four inches wide, in a single operation. It has generally been considered that the larger the area scanned in a single operation, the better the purpose of the device is served, since less work is required to scan a full page of data, and further since "registration" problems (the alignment of scanned portions of an image to correspond to the original image) are reduced by keeping the number of scans required to cover the image to a minimum. Therefore, the smaller hand held scanners are generally seen as inferring no particular advantage, as compared to the sheet type scanners, relating directly to the scanning process. Rather, the advantage of hand held scanners is that they are less expensive to produce, and generally much smaller and lighter than the sheet type scanners, such that the hand held scanners may be readily transported to the information sources.
As useful as are conventional hand held scanners, they are not well suited for the importation of selected portions of data. To the inventors' knowledge, no prior art scanner has allowed a user to easily scan selected portions of data into a computer. All prior art scanners have either required that relatively large blocks of a page be scanned together, or else have been ungainly and difficult to handle due to the conventional manner in which scanners are constructed.